China's final outpost, Jiayuguan was the last point of civilization before the Gobi Desert. This was also the strategic spot of the end of the Great Wall. The fort held the important job of protecting the Jade Pass that wove the Silk Road between the Qilianshan and Black Mountains. The fort was not completed until 1372, after the establishment of the Ming dynasty. Inside is the Great Wall Museum which exhibits the history of the wall from the Han to Ming eras.